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I am attempting to set up my first Proxmox hypervisor as a test server. I have managed to install Proxmox and set up some VMs however I can't get machines on my local LAN to connect to the Proxmox VMs.

• Host Subnet: 10.11.11.0/24


• Proxmox Host: 10.11.11.161

I have created two bridges one to act as a bridge to the WAN and the other as a private network.

Proxmox Host

auto lo
iface lo inet loopback

iface enp0s25 inet manual

auto vmbr0
iface vmbr0 inet static
 address 10.11.11.161
 netmask 255.255.255.0
 gateway 10.11.11.1
 bridge_ports enp0s25
 bridge_stp off
 bridge_fd 0

auto vmbr1
iface vmbr1 inet static
 address 10.11.12.1
 netmask 255.255.255.0
 bridge_ports none
 bridge_stp off
 bridge_fd 0

 post-up echo 1 > /proc/sys/net/ipv4/conf/vmbr0/proxy_arp
 post-up iptables -t nat -A POSTROUTING -s '10.11.12.0/24' -o vmbr0 -j MASQUERADE
 post-down iptables -t nat -D POSTROUTING -s '10.11.12.0/24' -o vmbr0 -j MASQUERADE

Connecting to VMs from Office LAN

The VMs are set up to use network vmbr1 from the Proxmox host, I can connect into the VMs ok.

However from my machine on the office lan 10.11.11.141 I can't see the VMs. I have tried adding the following static route to pass traffic for 10.11.12.0/24 subnet to the Proxmox host.

ip route add 10.11.12.0/24 via 10.11.11.161 dev eth0

Can anyone please advice on how I can connect the office LAN to the VLAN of Proxmox.

Thanks in advance.

If you need direct networking access from different IP network a router (gateway) should be used by definition. The gateway should belong to both IP networks and you should be using it by means of routing table. All-in-all it can be even a VM that's run on same server or the server itself.

You are using a Class A network but restrict yourself to class C. Change the subnet to 255.0.0.0 (class a) or 255.255.0.0 (class b) and you should be able to reach your clients. However if you are using the same connections use the same gateway or your may need to nat your connections

In reference check
https://en.m.wikipedia.org/wiki/Private_network

Just an example

C=10.0.0.1/255.255.255.0 can reach: 10.0.0.0/24 (10.0.0.254)
You can have 254 clients

B=10.0.0.1/255.255.0.0 can reach: 10.0.0.0/16 (10.0.255.254)
You can have 65534 clients

A=10.0.0.1/255.0.0.0 can reach: 10.0.0.0/8(10.255.255.254)
You can have 16777214 clients.

Your currently sutiation is the first but you want the second or third. Eben if you want to jump into another subnet
I. E
Client has 10.0.0.2/255.255.255.0 will not be able to Contact 10.0.1.2 due its Limit if you use 255.255.0.0 he will be able to do so.

This answer has been reduce to under stand the way it works but may not 100 percent correctly :)